German patent publication DE 10 2007 046 111 A1 discloses a portable, handheld work apparatus which is configured as a harvesting apparatus. A drive motor drives a shaking rod, which is hooked on a branch to be harvested via a hook, by means of a crank drive. In dependence on the rotational speed of the drive motor, a shaking vibration develops which detaches the fruit to be harvested from the shaken branch. Different degrees of ripeness of the fruits as well as different types of fruits require different shaking vibration frequencies, wherefore the user must adapt the drive rotational speed of the harvesting apparatus according to the fruits to be harvested, their degree of ripeness and the strength of the branch to be shaken.
In such handheld work apparatuses, continuous operation with reduced rotational speed can be advantageous. Advantageously, a rotational speed is set in dependence on the degree of ripeness of the fruit to be harvested and the strength of the branch to be shaken. Operation with reduced rotational speed can also be desirable for noise reduction. For this, the user must set the desired rotational speed by partially depressing the operating handle, which is uncomfortable and not very ergonomic when the user has to hold the operating handle in a partially depressed position for a relatively long period of time.
Also in chain saws having an electric motor for driving a saw chain, as is disclosed in United States patent application publication 2010/0218966, a reduced rotational speed can be practical for certain types of tasks, for example cutting branches.
U.S. Pat. No. 7,652,438 discloses a power characteristic line for an electric motor in an electric work apparatus for agriculture, forestry and gardening, whose power characteristic line has a maximum with respect to the rotational speed. During operation, the user selects different operating points on the characteristic line by changing the operating rotational speed. Operating points, which lie ahead of a power maximum of the characteristic line, are unstable operating points and are very difficult to maintain for a user; operating points beyond the maximum of the power characteristic line are stable operating points which the user can easily run up to and maintain.